SEOUL, South Korea (AP) -- South Korean prosecutors on Tuesday formally charged two former spy chiefs who were arrested last month over suspicions they used their agency's funds to make illegal payments to former President Park Geun-hye. Park was removed from office and arrested in March, and is being tried on broad corruption charges.

The Seoul Central District Prosecutors' Office said Nam Jae-joon and Lee Byung-kee were indicted on charges including bribery and causing unjust losses to state funds.

Prosecutors believe Nam and Lee took a combined 1.4 billion won ($1.2 million) from the National Intelligence Service's coffers and gave it to Park's close aides as paybacks for being named NIS directors. Nam and Lee reportedly acknowledged to prosecutors that they paid the money at the aides' request.

Nam and Lee served as the spy agency's chiefs between 2013 and 2015. Prosecutors are also investigating another of Park's former spy chiefs, Lee Byoung Ho, who served at the NIS from 2015 to 2017, over similar suspicions.

Park faces the possibility of a lengthy prison term over charges that she colluded with a friend to take tens of millions of dollars from companies in bribes and extortion.

She was arrested and jailed weeks after the Constitutional Court upheld an impeachment bill passed by lawmakers in December, formally removing her from office. Millions of people had angrily but peacefully marched in the streets for months calling for her ouster.